package com.fengjian.weixin.servlet;

import com.fengjian.weixin.service.CoreService;
import com.fengjian.weixin.utils.SignUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

/**
 * 请求处理的核心类
 * Created by fengjian on 14/11/27.
 */
public class CoreServlet  extends HttpServlet {

    protected Logger logger = LoggerFactory.getLogger(getClass());

    /**
     * 请求校验 （确认请求来自微信服务器）
     * @param request
     * @param response
     * @throws ServletException
     * @throws IOException
     */
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 微信加密签名
        String signature = request.getParameter("signature");
        // 时间戳
        String timestamp = request.getParameter("timestamp");
        // 随机数
        String nonce = request.getParameter("nonce");
        // 随机字符串
        String echostr = request.getParameter("echostr");
        logger.info("signature = {}, timestamp = {}, nonce = {}, echostr = {}", signature, timestamp, nonce, echostr);
        PrintWriter out = response.getWriter();
        // 通过检验signature对请求进行校验，若校验成功则原样返回echostr，表示接入成功，否则接入失败
        if (SignUtil.checkSignature(signature, timestamp, nonce)) {
            out.print(echostr);
        }
        out.close();
        out = null;
    }

    /**
     * 处理微信服务器发来的消息
     * @param request
     * @param response
     * @throws ServletException
     * @throws IOException
     */
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 将请求，响应的编码均设置为 UTF-8 （防止中文乱码）
        request.setCharacterEncoding("UTF-8");
        response.setCharacterEncoding("UTF-8");

        // 接受参数：微信加密签名、时间戳、随机数
        String signature = request.getParameter("signature");
        String timestamp = request.getParameter("timestamp");
        String nonce = request.getParameter("nonce");
        PrintWriter out = response.getWriter();
        // 请求校验
        if (SignUtil.checkSignature(signature, timestamp, nonce)) {
            String respXml = CoreService.processRequest(request);
            out.print(respXml);
        }
        out.close();
    }
}
